Telephone system



June 20, 1933. T. F. cRocKER 1,914,361

TELEPHONE SYSTEM Filed Nov. 9, 1951 2 Sheets-Sheet 1 Thomas F [I1-:1 :kar

June 20, 1933. T. F. cRocKl-:R

TELEPHONE SYSTEM Filed Nov. 9, 1931 2 Sheets-Sheet www Inl-JET'. DT' 'Tl-Lamas I1 Cracker Patented June 20, 1933 y Lenser www Pll

THOMAS F. CROCKER, GF CI-ICAGO, ILLINGIS, ASSIGNOR, BY MESNE ASSIGNMENTS, TO

ASSGSATED ELECTRC LABGRATORES,

TION OF DELAVIAR-E EMC., OF CHICAGO, LLENOIS, A CORPORA- TEJLEPHGNE SYSTEM Application led November 3, 1931.

This invention relates in general to telephone systems in which special service calls are handled at a central switchboard or desk, and is concerned primarily with the switchboard circuits and apparatus for use in such systems.

A principal object of the invention is the provision of new and improved circuits and apparatus for answering special service calls, and for transferring such calls, when necessary, to a chief operator or supervisor. Other objects and features of the invention will become apparent upon a further perusal of the specification.

By way of illustration the embodimentI of the invention in a multi-position information desk has been shown in the accompanying drawings. These drawings, comprising Figs. 1 and 2, show by means of the usual circuit diagrams certain representative apparatus of the regular or information positions, the night position, and the chief operators or supervisors position. Fig. 1 shows an information trunk TR which is accessible to an ordinary Strowger type selector and which terminates at one of the information positions in the answering key K. The line lamp L and the transfer key K1 are also provided at the information position for this trunk. A branch of the trunk extends to a night position at which is provided an answering key K2 andv a line lamp L1. At the information position, the answering key of the trunk TR and the answering keys of other similar trunks of this position are multiplied to the common conductors 13G-140 as indicated. Conductors such as 141-143 extend from each trunk to the banks of a finder switch, and conductors such as 144 and 145 extend from each trunk to the supervisors position. The distributor relay group D, which is also shown in Fig. 1, is common to all of the information positions and accordingly conductors 13G and 137 are multiply connected to the answering' keys at all positions.

ln Fig. 2 is shown an operators telephone set GT for one information position, an operators telephone set ST for the supervisors position, and a transfer circuit which Serial No. 573,774.

extends through the various information positions to the supervisors position. At the information positions there is provided the position equipment PTC and PTCl which includes keys K3, K4, and K5. `ley K5, incidentally, is common to all of the transfer circuits, of which there may be any number, which are multiply connected to the operators telephone set OT', as indicated. The keys K3 and K4' for the second information position are shown, but the operators telephone set, which will be the same as that shown for the firstposition, has been omitted. The position equipment STC the supervisors position includes keys KG and K7. Each transfer circuit is represented by two supervisory lamps L2 and L3 at each information position and by the lamps L4 and L5 at the supervisors position. rThe finder switch F, which is also shown in Fig. 2, is associated with the transfer circuit shown and has access to the various information trunks terminating in the information positions. Each transfer circuit will be provided with a .finder switch such as F, and its operation will be contiolled by the distributor relay group D shown in Fig. 1. l

Having described the invention generally, a detailed description of the operations involved in answering and transferring calls will now be given. For this purpose it will be assumed that a calling subscriber has operated a selector to extend a connection to the trunk line TR (Fig. 1). rlhe calling subscriber-s loop will be extended by way of conductors 133 and 135 and the upper and lower windings of relay 103 to ground and battery, reslliectively. Relay 103 operates, completes a circuit for relay 10i at contacts 125, and applies ring back tone to trunk conductor 135 by way of condenser 132 and contacts 126 and 123. Relay 104 operates, applies ground to release trunk conductor 134iat contacts 127 to hold up the selector and line switches of this connection. Relay 101i also completes a circuit for relay 105 at contacts 128 and completes a circuit for lamp L by` way of contacts 129, 122, and 116, and a parallel circuit for lamp L7 by way of conductor 144. Relay operates, completes an operating circuit for peg count meter 106 at contacts 131, and at contacts opens a circuit to permit the release of the selector, as will be explained subsequently.

On noting the'light-ed condition of lamp L, the operator at the information position in which the trunk TR terminates will answer the call by operating the key K to the right, thereby bridging the telephone set OT across conductors 133 and 135 by way of contacts 112 and 113, conductors 139 and 140, and contacts 212 and 213. A circuit is also closed from ground by way of the normally closed contacts 217 of key K5, contacts 215y conductor 138, contacts 114, lower winding of relay 102 tobattery. Relay 102 operates, prepares a busying circuit at contacts 120, which will be explained subsequently, completes a locking circuit for itself by way ofvcontacts 121 and 129, opens the circuit for lamps L and L7 at contacts 122, disconnect-s the ring back tone from the trunk at contacts 123, and at contacts 124 closes a circuit by way of conductor for lamp L6. Lamp L and lamp L7 are, accordingly, extinguished, and lamp LG glows to indicate to the supervisor that the call has been answered. rlhe information operator may now converse with the calling subscriber. Assuming that the information operator is able to supply the necessary information, after having done this, she will withdraw from the connection by restoring key K to normal. The original energizing circuit of relay 102 is opened at contacts 114 but this relay now remains operated over the locking circuit previously traced. When the calling subscriber restores his receiver, relay 103 will release and open thc circuit of relay 104, which will also release. Relay 104 removes ground from the release trunk conductor to permit the calling selector and line switch to release, and opens the circuit of relay 105 and the locking circuit for relay 102. These relays accordingly release and the equipment is in readiness to receive the next call. f

In case the calling subscriber should hang up before the operator restores the answering key K, the calling selector line switch will be released but the trunk will be marked busy to other calls. Upon the opening of the calling loop, relay 103 restores and opens the circuit of relay 104. Relay 104 releases and removes ground from release trunk conductor 134 and opens the circuit of relay 105. Relay 105 is slow to release and, during the interval between the release of relay 104 and the release of relay 105, the absence of ground vfrom conductor 134 permits the calling selector and the line switch to restore to normal. Upon the release of relay 105, ground by way of contacts 120 and 130 is rc-applied to conductor 134 to mark the trunk busy to the selectors. Relay 102 is, of course, held up over its original energizing circuit including contacts 114 of the answering key. lVhen the answering key is linally restored to normal, the circuit for relay 102 is opened, and that relay releases and removes the busying ground from release trunk conductor 134.

In the preceding call, it was assumed that the information operator was able to supply the information requested by the calling subscriber. lVhen the operator is unable to do this, she will transfer the call to the chief operator and so advise the calling subscriber. To effect the transfer, key K3 of the transfer circuit will be operated to the right, thereby bridging the operator-s telephone set OT across the talking conductors 256 and 262 of the transfer circuit by way of contacts 225 and 226. A circuit is completed by way of contacts 224 and conductor 258 for the busy lamps L3, L3', etc., at the Various positions and for lamp L5 at the supervisors position. The lamps glow to indicate the busy condition of this transfer circuit so that no other operators will attempt to connect thereto. A circuit for supervisory lamp L2 is prepared at contacts 223, a circuit for relay 201 is completed at contacts 227, and the signalling circuit is prepared at contacts 228. Relay 201 op erates, disconnects the operator-s telephone set from the information trunk at contacts 212 and 213, closes a new holding circuit over conductor 138 by closing contacts 214, and connects ground to holding conductor 261 of the transfer circuit at contacts 216. In case the information operator desires to talk with the supervisor before transferring the call, she will operate key K5 intermittently, thereby completing a circuit from battery, resistance 210, contacts 218 and 228, conductor 259, relay 203 to ground. Each time relay 203 operates, it completes a circuit for the lamp L4 at contacts 230. The intermittent lighting of lamp L4 will notify the supervisoll that an information operator wishes to speak with her. The supervisor will accordingly operate key K7 to the right, thereby bridging her telephone set across conductors 256 and 262 at contacts 247 and 248. Additional ground is applied to conductors 258 and 261 by the closure of con tacts 246 and 250, and a circuit is completed for relay 205 at contacts 249. The two operators may now converse without being overheard by the subscriber connected to the information trunk. In case the supervisor wishes to receive the call, she will so notify the information operator, who will then proceed to effect the transfer. The supervisor may remain connected to the transfer circuit or may restore key K7 to normal. Assuming that the key is restored to normal, the operation will be as follows: The information operator will operate key K4 to the left, thereby closing a circuit over contacts 222, conductor 146, contacts 155 to relay 150. Relay 150 on operating connects ground by way of contacts 151 and 157, conductor 136, contacts 111, lower winding of relay 101 to battery. Relay 150 also opens the circuit of relay 149 at contacts 159 and prepares the circuit for the linder switch F at contacts 160. Relay 101 operates, completes a holding circuit for its upper winding by way of contacts 117 and 110, conductor 137, contacts 158, relay 148 to ground. Relay 148 operates, opens the original energizing circuit of relay 101 at contacts 151 and thus prevents the operation of any other relays corresponding to relay 101 should an attempt be made to transfer a call on a different trunk. Relay 101 also marks the trunk line in the bank of the finder switch F by connecting ground to conductor 143 at contacts 118. Relay 148 completes a circuit for the stepping magnet of the finder switch by way of contacts y152 and 160, conductor 147, contacts 251, conductor 252, interrupter contacts of the stepping magnet, magnet '209 to batter 1. The magnet operates in its self-interrupting circuit and advancesthe wipers of the iinder step by step until wiper 265 encounters the contact associated with the trunk TR. This contact is grounded by way of conductor 143 and the ground by way of wiper 265, conductor 255.l contacts 235, relay 206 to battery energizes relay 206. Relay 206 opens the circuit of the stepping magnet at contacts 251 and at contacts 235 Yopens the short circuitv around the winding of relay 207. Relay 207 operates in series with relay l206 and completes a holding circuit for itself and relay 206 by way of contacts 238 and grounded conductorl 261. The talking conductors of the information trunk are now connected by way of conductors 141 and 142, wipers 263 and 264, conductors 253 and 254, contacts 239 and 240, contacts 241 and 242, to talking conductor 256 and 262 of the transfer circuit. A circuit is closed for lamp L4 by way of contacts 236, 231, .and 229, and the lamp glows to indicate to the supervisor that a call has been transferred. A circuit is also closed by way of contacts 237 and 233, conductor 257, and

contacts 223 for lamp L2 at the information position. Lamp L2 glows to indicate to the information operator that the finder has connected with the trunk, and the operator accordingly restores key K4 to normal.

f When the supervisor answers this call by operating key K7 to thel right, the previously described circuits controlled by this key are again closed, and relay 205 operates. The circuit for lamp L2 is opened at contacts 233 and a circuit is completed at contacts 234 for relay 204. Lamp L2 is extinguished to indicate to the information operator that the supervisor has answered the call. Relay 204 opens the circuit of lamp L4 at contacts 231 and at contacts 232 locks to ground by way of contacts 236. After determining that the call has been answered, the information operator will operate key K4 to the right or holding position and will restore keys K and K3 to normal. .Ground is now applied to conductors 258 and 261 by way of contacts 220 and 221, and a new circuit is prepared for lamp L2 at contacts 219. The restoration of key K of the trunk frees the operators circuit for other calls. The circuit for relay 101 is opened at contacts 110 and that relay restores. The holding circuit for relay 102 is opened at contacts 114, but a new circuit is completed by way of the upper winding ofthe relay, contacts 119, conductor 143, wiper 265, conductor 255, contacts 238, to grounded conductor 261 to which relays 206 and 207 are locked.

When the supervisor completes her conversation with the calling subscriber, she will restore key K7 to normal, opening the Various circuits previously closed by that key including the circuit for relay 205. Relay` 205 on restoring again completes a circuit for lamp L2, and the lamp glows to notify the information operator that the connection has been terminated. The information operator may recall the supervisor by operating lrey K5, as previously described, or if this is not required she will release the connection by restoring key K4 to normal. rlhe holding ground is removed from conductors 258 and 261 by the opening of contacts 220 and 221, and the circuit for lamp L2 is opened at contacts 219. Upon the removal of ground from conductor 261, relays 206 and 207 restore, and relay 102 of the trunk circuit also restores. Relay 207 opens the circuit for relay 204 and that relay restores. The equipment is accordingly returned to normal condition and in readiness to receive the next call.

The release of the switches used by the calling subscriber in extending the connection to the trunk is exactly the same as that described previously when the calling subscriber hangs up either before or after the operator has initiated the release.

What is claimed is:

1. Ina telephone system, a plurality of operators7 positions, a supervisors positien, a trunk line terminating in each operators position, a. transfer circuit extending through all of said operators positions to the supervisors position, a finder switch associated with said circuit and having access to all of said trunk lines, and means at each operatoris position for controlling the operation of said switch.

2. In a telephone system, a plurality of operators positions, supervisors position, trunk lines terminating at said operators positions, a transfer circuit extending through all of said operators positions to the supervisors position, a finder switch for connecting said circuit ,with any of said trunk lines, means common to all of said operators positions for marking a trunk line for connection to said circuit, and means individual to each operators position for controlling the operation of said last means.

3. In a telephone system, a switchboard including two positions, a trunk line terminating at one position, a transfer circuit connecting said two positions, a finder switch associated with said circuit, means at the first position for answering a call on said trunk line, means for establishing a talking connection between said two positions over said transfer circuit, and means at the first position for causing said switch to connect said line to said talking connection.

4. In a telephone system, a switchboard including two positions, trunk lines terminating at each position, a connecting circuit common to said positions, means at each position for answering a call over a trunk line terminating at the position, and means at each position for establishing an auxiliary connection with the calling trunk' line over said connecting circuit.

5. In a telephone system, a switchboard including two positions, lines terminating at each position, a trunk connectin said positions, a iinder switch associatec with said trunk, means at each position for answering a call on a line terminating at the position, and means at each position for operating said switch to connect the calling line and the trunk.

6. In a telephone system, an operators position, a line terminating at the position, a key for said line at said position, a trunk, two keys at the position for said trunk, a telephone set, means responsive to the operation of said line key for connecting the telephone set to the line, means responsive to the operation of the first trunk key for disconnecting the telephone set from the line and for connecting it to the trunk, and means responsive to the operation of the second trunk key for connecting the trunk with said line.

7. In a telephone system, an operators position, a line terminating at the position, a key for said line, a trunk terminating at the position, two keys for said trunk, a telephone set, a finder switch, means responsive to the operation of the line key for connecting the telephone set with the line, means responsive to the operation of the first trunk key for disconnecting the telephone set from the line and for connecting it to the trunk, and means responsive to the operation of the second trunk key for' operating the'inder switch to connect the trunk with the line.

8. In a telephone system, an operators position, a line and a trunk terminating at the position, a key 'for the line, two keys for the trunk, two signals for the trunk, a telephone set, means responsive to the operationof the line key for connectingthc telephone set with the line, means responsive to the operation of the rst trunk key for disconnecting the telephone set from the line, for connecting it to the trunk, and for operating one of said signals, means responsive to the operation of the second trunk key for connecting the trunk with the line, and means responsive to said last connection for operating the other of said signals.

9. In a telephone system, two operators positions, a line terminating at the first posi tion, a trunk connecting the positions, a finder switch associated with the trunk, means for extending a call over the line, means at the iirst position for answering the call, means at the first position for operating said switch into connection with the line to further extend the call to the second position via said trunk, means at the second position for answering the extended call, a signal at the first position operated responsive to said switch connecting with the line, and means responsive to the answering of the call at the second position for disabling said signal.

10. In a telephone system, two operators positions, a line terminating at the first position, a trunk connecting the two positions, a finder switch associated with the trunk, means for extending a call over the line, means at the first osition for answering the call, means at the rst position for operating said switch into connection with the line to further extend the call to the second position via said trunk, means at the second position for answering the extended'call, a signal at each position operated responsive to said switch connecting with the line, and means responsive to the answering of the call at the second position for disabling both of said signals.

l1. In a telephone system, two operators positions, a line terminating at the first position, a trunk connecting the positions, a inder switch associated with the trunk, means for extending a call over the line, means at the first position for answering the call, means at the first position for operating said switch into connection with the line to further extend the call to the second position via said trunk, a signal at each position operated responsive to said switch connecting with the line, means at the second position for answering the extended call, means for disabling both of said signals rcponsive to the answering of the call at thc second position, and means controlled from ICI the iirst position for reoperating the signal at the second position at will.

12. In a telephone system, two operators positions, a line terminating at the first position, a trunk connecting the positions, a signal at the first position, two signals at the second position7 means for operating the signal at the first position and one of the signals at the second position responsive to the extension of a call to said line, means at the lirst position for answering the call, means responsive to the answering of the call for disabling` both of said signals and for operating the other signal at the second position, means Jfor transferring the call to the second position via said trunk, and means for maintaining` said other signal operated until the transferred connection is released.

13. In a telephone system, a plurality of onerators ositions a su ervisors osition trunk lines terminating at said operators positions7 a transfer circuit extending through all of said operators positions to the supervisors position, a finder switch for connecting said circuit with any one of said trunk lines, means common to all of said operators positions for marking a trunk line for connection to said circuit, means individual to each operators position for controlling the operation of said last means, and means for preventing more than one of said last means for exercising control of said common means at one time.

In witness whereof, I hereunto subscribe l? my namel this 6th day of November, 1931.

THOMAS F. CROCKER. 

